A substrate processing apparatus generally includes a processing chamber capable of maintaining a vacuum environment, and a mounting table arranged in the interior (processing space) of the processing chamber for mounting a substrate thereon to thereby perform plasma processing or the like onto the substrate by supplying an RF power to the processing chamber. The mounting table is used to fulfill a temperature control function for setting a substrate at a predetermined temperature as well as a substrate supporting function to support the substrate in the processing chamber and a power supply function as an RF electrode.
The apparatus described in Japanese Patent Publication No. 2008-85329 (Patent Document 1) includes: an electrostatic chuck having a substrate supporting surface; a support base attached to the bottom surface of the electrostatic chuck with an adhesive; and a temperature control system. The electrostatic chuck has a center heating unit and an edge heating unit therein. The center heating unit is positioned below the central portion of the substrate supporting surface and the edge heating unit is positioned below the edge portion of the substrate supporting surface. Further, the support base has a cooling unit therein. The center heating unit, the edge heating unit and the cooling unit are controlled by the temperature control system so that the substrate temperature can be controlled to be maintained at a specific temperature. The electrostatic chuck and the support base are formed with ceramic and aluminum, respectively.
The apparatus described in Japanese Patent Application Publication No. 209-117443 (Patent Document 2) includes a support base in which dual circulation paths of heat transfer medium are provided, and a temperature control unit for supplying a heat transfer medium to each of the dual circulation paths. One circulation path is formed in a central portion of the support base and the other circulation path is formed in a side portion of the support base.
The temperature control unit has a heating unit for heating the heat transfer medium, a cooling unit for cooling the heat transfer medium and a bypass channel for making the heat transfer medium bypass the heating unit and the cooling unit. Heat transfer media discharged from exits of the respective circulation paths are supplied into the temperature control unit to be supplied into the heating unit, the cooling unit or the bypass channel. Further, flow rate control valves are provided at entrances of the respective circulation paths. The flow rate control valves allow the heat transfer media supplied from the heating unit, the cooling unit and the bypass channel to join together. With this configuration, the temperature-controlled heat transfer medium and the circulated heat transfer medium are joined to be a heat transfer medium at a predetermined temperature which is supplied into each of the circulation paths.
The apparatus described in Japanese Patent Application Publication No. 2008-509553 (Patent Document 3) includes a support base in which dual circulation paths of heat transfer medium are provided. One circulation path is provided in the first heating zone positioned at a central portion of the support base and the other circulation path is provided in a second heating zone positioned at a side portion of the support base. Since each of the circulation paths is independently connected with a heat exchanger, the circulating speed (flow rate) or the temperature of the heat transfer medium, or the combination thereof is controlled, and thus, the temperature of the substrate can be set at a predetermined level.
Patent Document 1: Japanese Patent Application Publication No. 2008-85329
Patent Document 2: Japanese Patent Application Publication No. 2009-117443
Patent Document 3: Japanese Patent Application Publication No. 2008-509553
The mounting table described in Patent Document 1 has a laminated structure configured with a plurality of members stacked by using an adhesive so that the substrate supporting function, the power supply function and the temperature control function can be achieved.
In order to stably maintain an adhesive strength, the adhesive for attaching the members is heat resistant. Accordingly, when a vicinity temperature around adhesive becomes equal to or greater than the heat resistant temperature of the adhesive, the adhesive strength deteriorates, and thus, the attached members may become detached. Further, in a case where a thermal conductivity as a physical property of each member is remarkably low, heat transferring is interrupted, and thus, a temperature control range of the substrate may not be satisfied. Furthermore, each cooling unit described in Patent Documents 1 to 3 has a limit to its cooling capacity, i.e., an amount of heat taken away from the substrate per unit time. Therefore, cooling control cannot be executed at a temperature higher than a cooling temperature limit of the cooling unit.
As described above, the temperature control range of the substrate, which is set by the temperature control function of electrostatic chuck, is limited by the physical properties of the configuration members of the electrostatic chuck and the adhesive material, and the cooling capacity of the cooling unit.